prpower.c

这个linux源代码是很全面的~基本完整了~使用c编译的~由于时间问题我没有亲自测试~但就算用来做参考资料也是非常好的

/*****************************************************************************
 *
 * Module Name: prpower.c
 *   $Revision: 32 $
 *
 *****************************************************************************/

/*
 *  Copyright (C) 2000, 2001 Andrew Grover
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */


/* TBD: Linux specific */
#include <linux/sched.h>
#include <linux/pm.h>
#include <asm/io.h>

#include <acpi.h>
#include <bm.h>
#include "pr.h"

#define _COMPONENT		ACPI_PROCESSOR
	MODULE_NAME		("prpower")


/****************************************************************************
 *                                  Globals
 ****************************************************************************/

extern FADT_DESCRIPTOR		acpi_fadt;
static u32			last_idle_jiffies = 0;
static PR_CONTEXT		*processor_list[NR_CPUS];
static void			(*pr_pm_idle_save)(void) = NULL;
static u8			bm_control = 0;


/* Used for PIIX4 errata handling. */
unsigned short			acpi_piix4_bmisx = 0;


/****************************************************************************
 *                             External Functions
 ****************************************************************************/

/****************************************************************************
 *
 * FUNCTION:    pr_power_activate_state
 *
 * PARAMETERS:
 *
 * RETURN:
 *
 * DESCRIPTION:
 *
 ****************************************************************************/

void
pr_power_activate_state (
	PR_CONTEXT		*processor,
	u32			next_state)
{

	PROC_NAME("pr_power_activate_state");

	if (!processor) {
		ACPI_DEBUG_PRINT ((ACPI_DB_ERROR, "Invalid (NULL) context.\n"));
		return;
	}

	processor->power.state[processor->power.active_state].promotion.count = 0;
	processor->power.state[processor->power.active_state].demotion.count = 0;

	/*
	 * Cleanup from old state.
	 */
	switch (processor->power.active_state) {

	case PR_C3:
		/* Disable bus master reload */
		acpi_hw_register_bit_access(ACPI_WRITE, ACPI_MTX_DO_NOT_LOCK,
			BM_RLD, 0);
		break;
	}

	/*
	 * Prepare to use new state.
	 */
	switch (next_state) {

	case PR_C3:
		/* Enable bus master reload */
		acpi_hw_register_bit_access(ACPI_WRITE, ACPI_MTX_DO_NOT_LOCK,
			BM_RLD, 1);
		break;
	}

	processor->power.active_state = next_state;
	
	return;
}


/****************************************************************************
 *
 * FUNCTION:    pr_power_idle
 *
 * PARAMETERS:  <none>
 *
 * RETURN:
 *
 * DESCRIPTION:
 *
 ****************************************************************************/

void
pr_power_idle (void)
{
	PR_CX			*c_state = NULL;
	u32			next_state = 0;
	u32			start_ticks, end_ticks, time_elapsed;
	PR_CONTEXT		*processor = NULL;

	PROC_NAME("pr_power_idle");

	processor = processor_list[smp_processor_id()];

	if (!processor || processor->power.active_state == PR_C0) {
		return;
	}

	next_state = processor->power.active_state;

	/*
	 * Check OS Idleness:
	 * ------------------
	 * If the OS has been busy (hasn't called the idle handler in a while)
	 * then automatically demote to the default power state (e.g. C1).
	 *
	 * TBD: Optimize by having scheduler determine business instead
	 *      of having us try to calculate it.
	 */
	if (processor->power.active_state != processor->power.default_state) {
		if ((jiffies - last_idle_jiffies) >= processor->power.busy_metric) {
			next_state = processor->power.default_state;
			if (next_state != processor->power.active_state) {
				pr_power_activate_state(processor, next_state);
			}
		}
	}

	disable();

	/*
	 * Log BM Activity:
	 * ----------------
	 * Read BM_STS and record its value for later use by C3 policy.
	 * (Note that we save the BM_STS values for the last 32 cycles).
	 */
	if (bm_control) {
		processor->power.bm_activity <<= 1;
		if (acpi_hw_register_bit_access(ACPI_READ, ACPI_MTX_DO_NOT_LOCK, BM_STS)) {
			processor->power.bm_activity |= 1;
			acpi_hw_register_bit_access(ACPI_WRITE, ACPI_MTX_DO_NOT_LOCK,
				BM_STS, 1);
		}
		else if (acpi_piix4_bmisx) {
			/*
			 * PIIX4 Errata:
			 * -------------
			 * This code is a workaround for errata #18 "C3 Power State/
			 * BMIDE and Type-F DMA Livelock" from the July '01 PIIX4
			 * specification update.  Note that BM_STS doesn't always
			 * reflect the true state of bus mastering activity; forcing
			 * us to manually check the BMIDEA bit of each IDE channel.
			 */
			if ((inb_p(acpi_piix4_bmisx + 0x02) & 0x01) ||
				(inb_p(acpi_piix4_bmisx + 0x0A) & 0x01))
				processor->power.bm_activity |= 1;
		}
	}

	c_state = &(processor->power.state[processor->power.active_state]);

	c_state->utilization++;

	/*
	 * Sleep:
	 * ------
	 * Invoke the current Cx state to put the processor to sleep.
	 */
	switch (processor->power.active_state) {

	case PR_C1:
		/* Invoke C1 */
		enable(); halt();
		/*
	 * TBD: Can't get time duration while in C1, as resumes
		 *      go to an ISR rather than here.
		 */
		time_elapsed = 0xFFFFFFFF;
		break;

	case PR_C2:
		/* See how long we're asleep for */
		acpi_get_timer(&start_ticks);
		/* Invoke C2 */
		acpi_os_read_port(processor->power.p_lvl2, NULL, 8);
		/* Dummy op - must do something useless after P_LVL2 read */
		acpi_hw_register_bit_access(ACPI_READ, ACPI_MTX_DO_NOT_LOCK, BM_STS);
		/* Compute time elapsed */
		acpi_get_timer(&end_ticks);
		/* Re-enable interrupts */
		enable();
		acpi_get_timer_duration(start_ticks, end_ticks, &time_elapsed);
		break;

	case PR_C3:
		/* Disable bus master arbitration */
		acpi_hw_register_bit_access(ACPI_WRITE, ACPI_MTX_DO_NOT_LOCK, ARB_DIS, 1);
		/* See how long we're asleep for */
		acpi_get_timer(&start_ticks);
		/* Invoke C3 */
		acpi_os_read_port(processor->power.p_lvl3, NULL, 8);
		/* Dummy op - must do something useless after P_LVL3 read */
		acpi_hw_register_bit_access(ACPI_READ, ACPI_MTX_DO_NOT_LOCK, BM_STS);
		/* Compute time elapsed */
		acpi_get_timer(&end_ticks);
		/* Enable bus master arbitration */
		acpi_hw_register_bit_access(ACPI_WRITE, ACPI_MTX_DO_NOT_LOCK,
			ARB_DIS, 0);
		/* Re-enable interrupts */
		enable();
		acpi_get_timer_duration(start_ticks, end_ticks, &time_elapsed);
		break;

	default:
		ACPI_DEBUG_PRINT ((ACPI_DB_ERROR, "Attempt to use unsupported power state C%d.\n", processor->power.active_state));
		enable();
		break;
	}

	/*
	 * Promotion?
	 * ----------
	 * Track the number of successful sleeps (time asleep is greater
	 * than time_threshold) and promote when count_threshold is
	 * reached.
	 */
	if ((c_state->promotion.target_state) && 	
		(time_elapsed >= c_state->promotion.time_threshold)) {

		c_state->promotion.count++;
 		c_state->demotion.count = 0;

		if (c_state->promotion.count >= c_state->promotion.count_threshold) {
			/*
			 * Bus Mastering Activity, if active and used
			 * by this state's promotion policy, prevents
			 * promotions from occuring.
			 */
			if (!bm_control || !(processor->power.bm_activity & c_state->promotion.bm_threshold))
				next_state = c_state->promotion.target_state;
		}
	}

	/*
	 * Demotion?
	 * ---------
	 * Track the number of shorts (time asleep is less than
	 * time_threshold) and demote when count_threshold is reached.
	 */
	if (c_state->demotion.target_state) {
			
		if (time_elapsed < c_state->demotion.time_threshold) {

			c_state->demotion.count++;
			c_state->promotion.count = 0;

			if (c_state->demotion.count >=
				c_state->demotion.count_threshold) {
				next_state = c_state->demotion.target_state;
			}
		}

		/*
		 * Bus Mastering Activity, if active and used by this
		 * state's promotion policy, causes an immediate demotion
		 * to occur.
		 */
		if (bm_control && (processor->power.bm_activity & c_state->demotion.bm_threshold))
			next_state = c_state->demotion.target_state;
	}

	/*
	 * New Cx State?
	 * -------------
	 * If we're going to start using a new Cx state we must clean up
	 * from the previous and prepare to use the new.
	 */
	if (next_state != processor->power.active_state) {
		pr_power_activate_state(processor, next_state);
		processor->power.active_state = processor->power.active_state;
	}

	/*
	 * Track OS Idleness:
	 * ------------------
	 * Record a jiffies timestamp to compute time elapsed between calls
	 * to the idle handler.
	 */
	last_idle_jiffies = jiffies;

	return;
}


/*****************************************************************************
 *
 * FUNCTION:    pr_power_set_default_policy